Europe was starkly reminded Wednesday that it still has much to do in bringing peace to the volatile, violent remnants of former Yugoslavia.
An assassin felled the reformist and pro-Western prime minister of Serbia, Zoran Djindjic, the charismatic philosopher-politician who organized the ouster of dictator Slobodan Milosevic in 2000.
The sniper killing of Mr. Djindjic, presumably arranged by a gang boss due to be arrested soon, should also remind the Serb people to keep alive the spirit of reform that led them to rise up against Mr. Milosevic.
The Balkans remain a backwater of Europe partly because of the many 20th-century assassinations, fueled by ethnic nationalism, religious bigotry, radical ideology, or thuggery.
Replacing the modernizing Djindjic won't be easy for the Serbs. He was able to unify many political factions by calm persuasion and worked with the West to send war-criminal suspects to The Hague for trial. He also ended the use of Yugoslavia as a country name through Serbia's new arrangement with Montenegro. And he tried to bring economic reform and the rule of law to a country torn apart by four wars that Milosevic started.
Both the European Union and the United States must now rethink the political pressure they've used through their aid to push along the reforms that Djindjic began. In a land where vengeance and blind nationalism often rules, reformers like Djindjic need to be nurtured with care. And the 10 million Serbs need to see the benefits of steady reform.